Zigzag sewing machine with control device for producing composite enclosed-area stitch patterns



Apnl 2, 1963 H. THEENHAUSEN r-rrAL 3,083,657

ZIGZAG sswmc MACHINE WITH CONTROL DEVICE FOR PRODUCING COMPOSITE ENCLOSED-AREA STITCH PATTERNS Filed Aug. 12, 1959 9 Sheets-Sheet 1 m/enzors Heinric/a mean/la. use/1 EN ETAL 3,083,657 WITH CONTROL DEVICE ITE ENCLOSED-AREA Apnl 2, 1963 H. THEENHAUS ZIGZAG SE c; MACHINE FOR PROD ING COMPOS STITCH PATTERNS Filed Aug. 12, 1959 9 Sheets-Sheet 2 .z'm errzam H i h 7/) e en/ia use n W/'//y Siebra sse ETAL 3,083,657 I CONTROL DEVICE TE ENCLOSED-AREA Apnl 2, 1963 H. THEENHAUS ZIGZAG SEWING MACHINE w FOR PRODUCING COMPOSI STITCH PATTERN Filed Aug. 12, 1959 9 Sheets-Sheet 3 W/fly sl ebrasse Apr1l2, 1963 H. THEENHAUSEN El'AL 3,083,657

ZIGZAG SEWING MACHINE WITH CONTROL DEVICE FOR PRODUCING COMPOSITE ENCLOSED-AREA STITCH PATTERNS 9 Sheets-Sheet 4 Filed Aug. 12, 1959 .l'm emar's He/nr/c/z T/zeen Aausen W/Y/y S/eb r'ass e Apnl 2, 1963 H. THEENHAUSEN ETAL ,083,

ZIGZAG SEWING MACHINE WITH CONTROL DEVICE FOR PRODUCING COMPOSITE ENCLOSED-AREA Y STITCH PATTERNS Filed Aug. 12, 1959 9 Sheets-Sheet 5 MANUAL AUIUMATIC Inventor's Hem r/c/v T/reen/rausen W/// 5/6 bra sse April 1963 H. THEENHAUSEN ETAL 3,083,657

ZIGZAG szwmc; MACHINE WITH CONTROL DEVICE FOR PRoDucmG COMPOSITE ENCLOSED-AREA smca PATTERNS Filed Aug. 12, 1959 9 Sheets-Sheet 6 Inventor's He/hr/cfi 7% e en/9a. us an Wf/ly S/erasse Apnl 2, 1963 H. THEENHAUSEN EI'AL 3,033,657

ZIGZAG SEWING MACHINE WITH CONTROL DEVICE FOR PRODUCING COMPOSITE ENCLOSED-AREA STITCH PATTERNS Filed Aug. 12, 1959 9 Sheets-Sheet 7 einrich Tbeenha usen WIl/y sl'ebr'a. ss

Ap 2, 1963 H. THEENHAUSEN ETAL 3,083,657

ZIGZAG SEWING MACHINE WITH common. DEVICE FOR PRODUCING COMPOSITE ENCLOSED-AREA STITCH PATTERNS Flled Aug 12, 1959 9 Sheets-Sheet 8 llll .70 vemo rs fl E w w 5 fm m2 im 2 W 6 y April 2, 1963 I H. THEENHAUSEN EIAL 3,083,657

ZIGZAG SEWING MACHINE WITH CONTROL DEVICE FOR PRODUCING COMPOSITE ENCLOSED-AREA STITCH PATTERNS Filed Aug. 12, 1959 9 Sheets-Sheet 9 4 f/earaxc United States Patent 3,983,657 ZIGZAG SEWING MACHENE WITH CGNTRQL DEVECE FOR PRGDUCDJG (ZGMPQSHE EN- LOSED-AREA STITCH PATTERNS Heinrich Theenhausen, Eieiefeld, and Willi Siehrasse, Hecpen, near Eielefeld, Germany, assignors, by memo assignments, to Anirer-Phoenix Nahrnaschinen A.G., Bielefeid, Germany, a corporation of Germany Filed Aug. 12, 1959, Ser. No. 833,216 Ciaims priority, application Germany Aug. 14, 1958 tjlaims. (Cl. 112-458) Our invention relates to an automatic zigzag sewing, machine with control means for producing fancy stitch patterns of the enclosed-area type, particularly button holes.

There are known zigzag sewing machines in which the stitch width (transverse to the feed direction), the stitch length (in the feed direction), the stitcr -area position as well as the feed direction are automatically controlled by respective cam disks driven from the mechanism of the sewing machine. Such an automatic sewing machine affords the production of fancy stitch patterns that are closed upon themselves, for example buttonholes. However, in these prior machines the control of the slider which determines the needle-bar position and the feed direction is relatively slow and they therefore inevitably produce intermediate stitches which do not belong to one or the other component (such as the side bars and the cross tacks of a buttonhole) of the pattern to be produced, so that the appearance of the completed pattern is unclean at the transition localities. This slow control of the needle-bar position and of the material feeder device is a consequence of the gradual ascending and descending portions in the contour of the control cams since, in order to secure the satisfactory functioning of all machine parts, these cams must not possess abrupt transitions.

The known control devices permit automatic control of the side-bar and cross-tack stitches and thus produce buttonholes of difierent lengths. However, the automatically rotating set of control cams can be stopped only by stopping the sewing machine itself or by shifting a manual control member for the stepping switch mech anism into its inactive position. For these reasons, the person using the machine must exercise considerable attention for stopping the set of control cams only in a definite position of its circumference if he is to prevent a sewing over of an already finished seam. Furthermore, when the over-sewing of a button hole or other pattern completely closed upon itself is completed, it is dificult with the known device to commence the sewing of a new buttonhole, because the proper starting point of the new cam actuated cycle becomes inaccurately located or may have been passed, with the result that the seams of the buttonholes may appear unclean.

It has also been proposed to produce button holes by means of automatically rotating control cams in sewing machines in such a manner that only a portion of the entire area pattern is produced automatically whereas another portion of the pattern is completed while the control cams are at a standstill. For this purpose, the control mechanism is provided with a cam disk which carries a dog pin for prematurely disconnecting the cam drive. A special manual setting member is provided to permit thereafter turning the cam disks by hand in order to 3,083,657. Patented Apr. 2, 1963 complete the closed-type sewing pattern, and thereafter to initiate renewed operation of the automatic cam drive. However, this device does not permit the operator, when using one and the same set of cams, to produce buttonholes of different lengths, because for each cam set there is a predetermined constant transmission ratio between the arm shaft and the cam drive shaft for rotation of the individual control cams.

it is therefore an object of our invention to improve control devices of the above-mentioned type in zigzag sewing machines in such a manner \as to facilitate and imrove the production of buttonholes or other enclosedarea patterns by means of automatically rotating cam disks while also securing a more accurate and cleaner appearance of the buttonhole or other pattern without placing exacting requirements upon the attention or skill of the operating sewing personnel.

It is a further object of the invention to provide a control device for a zigzag sewing machine which effects an abrupt switching action relative to the control cams from one control sector of a cam, which produces one portion of a compound pattern, to another control sector of the control cam which produces another portion of the pattern, and thus to achieve automatic and accurate transition between controlled sewing cycles, or between portions of the same sewing cycle, while retaining a gradual contour change in the shape of the cam surface itself.

To achieve these objects, our invention is predicated upon the use of a zigzag sewing machine with an automatic control device for the production of closed-area stitch patterns, particularly buttonholes, with the aid of a rotating set of cams for automatically controlling the needle-bar movements and the feed of the material being sewed. Machines of this general type are more fully described in copending applications Serial Nos. 514,178, now Patent No. 2,929,344, granted March 22, 1960; 515,160, now Patent No. 2,966,878, granted January 3, 1961; 660,878, and 665,555, all assigned to the assignee of the present invention. Relating to such a machine, it is a feature of our invention to provide a circularly acting force-storing device between the portion of the control means driven from the arm shaft of the machine on the one hand, and the set of cams for controlling the stitching width, the stitching area and the feed on the other hand, the force storer having the effect of producing an abrupt switching of the control motion from one control sector to the next sector.

By virtue of the abrupt jump in the control of the cams, from one control sector to the next, any possibility of intermediate stitches forming between the individual pattern stitches proper, such as the side-bar stitches and the cross-tack stitches of a buttonhole is eliminated.

In order to avoid further disadvantages of the known methods and devices for producing closed patterns such as buttonholes by means of automatically rotating conrtrol cams, we further provide, according to another feature of our invention, an automatic coupling device which renders the driving means selectively active and inactive in one and the same position of the set of cam disks.

The latter feature affords the considerable advantage with automatically rotating control cams that certain sewing-stitch patterns, for example the last side-bar stitches of a buttonhole, are controlled while the set of cams is at standstill. This is particularly significant in view of the fact that diiferent fabrics or other materials to be sewed yention.

are subjected to respectively difierent amounts of feed motion even though the cam control may call for a constant feed. Furthermore, differences may occur between the forward and reverse travel of the fabric when producing enclosed-area stitch patterns, and such differences can be compensated for with the present invention by virtue of the fact that the last portion of the sewing travel is controllable while the set of cams remains at rest.

The invention will be further described with reference to two embodiments of control devices according to the invention, illustrated by way of example on the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of the first control device, the section being taken along the line A-B indicatedin FIG. 4.

FIG. 2' shows a top view of the same device, and

FIG. 3 is a lateral view of the device.

FIG- 4 illustrates a top view of the device partly in cross section along the line CD indicated in FIG. 1.

FIGS. 5 and 6 are top views cut away to show details of the same control device.

- FIG. 7 is a sectional top view onto part of the sewing machine of FIG. 14 with the top housing removed to show the control device for positioning of the stitching area and for the motif frequency.

' FIG. 8 is a lateral, sectional view of the control device for the position of the stitching'area, the section being taken along the line VIII-VIII indicated in FIG. 7.

FIG. 9 shows, partly in section, a separate top view of a stepping mechanism which forms part of the same devices'as represented in FIG. 7. V FIG. 10 is a partly sectional view of the automatic control device forthe stitching-area position, the stitching width, and the material feed.

'FIG. 11 is a partially sectional view of the coupling device.

FIG. 12. shows in lateral view the automatic control devicefor the stitching-area position, the stitching width, and the feed.

FIG. 13 shows the device of FIG. 2 in plan view.

FIG. 14 is a'front view, seen from the operators position of, a zigzag sewing machine according to the in- FIG. -15' is a plan view of the stitch control fork and related parts. FIG; 16 is a fragmentary front view, in section, of the material feeding device.

Inthe copending application Serial No. 515,160, filed June 13, 1955, by Heinrich'Theenhauser and Otto Wank, assigned to the assignee of the present invention, there is described a zigzag. sewing. machine whose control cams are driven from the arm shaft by means of a cam mechanism, with a stepping switch and a roller coupling interposed between the arm shaft and the cam shaft. The embodiments illustrated in the present application and described presently relate'generally to a machine of the type illustrated and described in that copending application.

In accordance with the conventional design of 'sewing machines, those illustrated and. described hereinbave a base B (FIG. 14) on which a machine housing 55 is mounted. This housing 55 forms a hollow standard joined with the base and has a horizontal hollow arm 7 portion 52a (FIGS. 7, 8), which remote from the standard, merges with a dependent needlebar housing located above, and upwardly spaced from the sewing'area on the top surface of the base. The interior of the housing 55 comprises the needle-bar drive mechanism as well as most of the parts appertaining to the control mechanism according to the invention. The open top of the housing is closed by a hinged or removable cover 115a. The conventional presser foot C forms an exchangeable part of an assembly'D which extends'vertically upward into the housing where it comprises a vertical rod P, shown in FIGS. 14 and 15. As usual, the presser-foot assembly can be lifted and lowered. The

vertically reciprocable needle bar N (FIGS. 14, 15) carrying the sewing needle M extends parallel to the resser-foot assembly. Its operation for straight sewing is as usual and is therefore not further described.

Aside from its vertical reciprocations, the needle bar N is also capable of lateral swinging movements as required for zigzag operation, These lateral movements occur about the axis of the resser-foot rod P in a horizontal direction substantially parallel to the plane of illustration of FIG. ,14, and they are accompanied by a corresponding swinging movement of the presser foot. The needle bar N is vertically slidable in a bearing sle eve S (FIG. 15). Sleeve S forms part of a swing frame F which is mounted on the resser-foot rod P and is rotatable together with rod P about the vertical axis of rod P. During straight sewing the swing frame F is stationary, but for zigzag work an oscillating motion is imparted to the frame F by means of a connecting rod R which extends through the horizontal arm portion 52a of the machine housing 55 to an assembly of controlmechanisms mounted in the housing.

It will be recognized from FIG. 15 that the zigzag stitching width in the directions of the double-headed arrow A corresponds to the amplitude of any oscillations transmitted by rod R to swing frame F, and that the.

stitching location or area is determined by the center or zero position of these oscillations. The stitch'controlling oscillations come about and are controlled as follows:

During the machine operation, a continuously rotating is displaceable in two Ways, namely angularly about its axis and also linearly. Assume first that the member 345 occupies the illustrated position of FIG. 15 in which its groove has the direction of the indicated axis O-O. When the cam 349 is rotating, the fork 348 and rod R will oscillate about the axis of the needle bar N while the slide block 346 will reciprocatealong the groove of member 345. Hence no swinging motion is transmitted to the needle bar and the lateral stitching width is zero.

Now assume that the member 345 is turned clockwise (as viewed in FIG. 15 so that the groove extends along the axis T-T. Then during the oscillations of fork 348 a lateral component of motion is transmitted through rod R to the swing frame F so that the needle bar N will oscillate about the axis of presser-foot rod P with an amplitude dependent upon the amount of angular displacement of member 345 from the zero axis ()O. In

this manner, any desired amplitude and hence sitching,

14) or automatically by operation of a selected, exchange able cam disk 192 (FIG. "10), depending upon whether, 7 a control member 59 is placed in manual or automatic position. 7

Referring to FIG. 15, the slide-waymem'ber 345 is further capable of linear displacement toward or away from the resser-foot rod P. Any such displacement is shared 7 by the pivot pin 347 of the stitch control fork 348 so that the center position or area of the oscillations transmitted from cam 349 to the needle bar N is shifted accordingly. The slide-way member 345has a pivot mounted on a slide plate 336 (FIG. 7), and this platecan be shifted either manually by a control lever 56, 59 (FIGS. 8, 14) or by the cam disk 1 93 acting through link 116, thus controlling the stitching area.

' The automatic control of the material feed is carried out by the camdisk 194 acting upon the feeder fork arm 462 (FIG. 16) through the medium of cam feeler lever 124 and through a series of linkages such as are more fully described and illustrated in the above-mentioned copending application Serial No. 665,555 of Albert Klaar et al., assigned to the assignee of the present invention. During rotation of the arm shaft 346:: (FIG. 14) an eccentric (not illustrated) imparts lateral deflections to the feeder fork 462. Depending upon the position of a movable block (not illustrated), the feeding fork 462 then deflects in its longitudinal direction or transversely thereto as determined by its guidance in a slideway of the aforementioned movable block. The lifting motion, constrainedly following therefrom, is transmitted through the crank 463 and the shaft 464 onto the feeder crank 465 (FIG. 16) which acts upon the material pusher 457 through the pusher carrier 466.

The device shown particularly in FIGS. l to 6 serves for automatically controlling the production of stitch patterns which are closed upon themselves, and particularly for the production of buttonholes which are composed of two side bars along the buttonhole opening and two cross tacks at the respective ends of the buttonhole. The drive shaft 1 (FIG. 1) of the control device has a central bore 2 engaged by a stub shaft 5 driven preferably from a stepping mechanism as exemplified by the one shown in FIG. 9 and described further below. The stub shaft '3 is journalled in the arm structure 4 of the sewing machine and, when in operation, entrains the drive shaft 1 for stepwise motion. The drive shaft 1 forms several steps with annular shoulders and is guided in the correspondingly stepped base plate 6 of the mechanism. The base plate 6 is firmly secured to the machine arm 4 by bolts or other suitable means (not illustrated). The cam disks 8, 9 and are rotataoiy journalled on the extension 7 of the drive shaft and these disks are, namely a cam disk 8 for controlling the Stitching area position, a cam disk 9 for controlling the stitching width, and a cam disk 10 for controlling the stitching length and the feed direction. The cams cooperate with respective cam followers 11, 12 and 13 (FIG. 4) and are connected by a screw bolt 14 (FIG. 1) with a control member 15 mounted on drive shaft and designed as described below to serve as a spring housing. Located within the member 15 is a spiral spring '16 serving as a force storer. The innermost turn 17 of spring 16 is provided with a rectangular hole 18 (FIG. 4) engaged by an entrainer wedge 19 of the drive shaft 1. The outermost turn 2%) of the spiral spring 16 is fastened to the inner wall 21 of the control member 15. A sleeve 24, fastened to drive shaft 1 by means of a clamping plate 22 and a screw 23, covers the spring 16 as well as a portion of control member 15.

Riveted to the base plate 6 (FIG. 1) is a pin 25 upon which a sleeve 26 is seated. Joined with the sleeve 26 is a latch lever with two arms 27 and 31 (FIG. 2) which, together with sleeve 26, can perform pivotal motion about the axis of pin 25. The latch lever has a bore 28 in lever arm 27 (FIGS. 2, 5, 6) engaged by one end of a helical spring 39 whose other end abuts against a pin 29 fastened to the base plate 6 16$. 3, 6). The spring 3% imposes upon the latch lever 27, 31 a biasing force in the clockwise irection relative to FIG. 2 so that a latch nose 32. of lever arm 31 can catch behind a stop 34 (FIGS. 2, 6) of control member 15, the stop 34 consisting of rubber or synthetic material.

Disposed on the outer periphery of control member 15 are further stops 35 to 33 (FIG. 2) corresponding to further closed-type stitch patterns to be produced. Rotatably seated on the sleeve 26 (FlG. l) is a release lever 39 (FIGS. 1, 2, 5, 6) which is adjustable on the arm 31 of the latch lever by means of a screw 46. The levers 27, 31 and 39 are prevented from axial displacement by means of a lock washer 42 engaging a peripheral groove 41 of the pivot pin 25.

The release lever 39 has a nose 43 cooperating with dogs 44 to 47 which are mounted on the periphery of the sleeve 24 and are displaceable along the periphery and adapted to be fastened in the proper positions by means of fastening screws 48, 49. The arm 27 of latch lever 27, 31 merges into a hook-shaped latch nose 50 for cooperation with the stops 34 to 33. The latch lever 27, 31 carries a manually actuable extension 51 (FIGS. 2, 5, 6) which serves to adjust the starting point of a compound stitch pattern, such starting point being for example, the first side bar of a buttonhole. The upper portion 52 of sleeve 24 (FIG. 3) is knurled to facilitate manual manipulation.

The operation of the control device described so far is as follows. 7

The shaft 1 of the control device is driven counterclockwise relative to FIG. 4 from the arm shaft 346a (FIG. 14) through conventional means, preferably worm gears, and through an intermediate stepping mechanism 91 (FIG. 9) acting through step shaft 3. At the beginning of the sewing operation for producing a buttonhole, such counterclockwise rotation of shaft 1 places the spiral spring 16 under tension by means of the entraincr wedge 1? mounted on shaft 1. The spiral spring 16 has a slight initial tension and becomes wound up when the shaft 1 with its wedge 19 commences rotating counterclockwise (relative to FIG. 4). The control member 15, which forms the housing for the spiral spring 16, is prevented from rotating by means of the stop 34- (FIGS. 2, 5) which is engaged by the latch nose 32 of the latch lever 27, 31 biased clockwise (relative to FIG. 5) by the helical springs 39 (FIGS. 1, 3). Consequently, the control cams 8, 9 and 1t), and thus also their respective followers 11, 12 and 13 (FIG. 4) are kept arrested in their starting positions while the first side bar of a buttonhole is being produced, namely in the first control position of the control cams 8, 9 and 16.

As soon as the nose 43 of release lever 3? runs onto the slanting dog 44 of the sleeve 24 driven counterclockwise from shaft 1 (relative to FIGS. 2, 5, 6), the latch nose 32 of latch lever 27, 31 is withdrawn from the stop 3 of the control member 15. As a result, the control member 15, carrying the control cams 8, 9, 14 is turned counterclockwise (relative to FIGS. 2, 5 and 6) by the action of the force-storing spring 16 to such an extent that the stop 38 of control member 15 is caught by the hookshaped latch nose 5%) of lever arm 2", thus preventing a further rotation of the control member 15. This rotary motion of control member 15 from nose 32. to nose 59, however, is so slight that it does not release any switching movement of the control cams S, 9 and 10. As soon as the dog 44 has run beyond the nose 43 of release lever 39, lever 39 has been pivoted counterclockwise to disengage latch nose 32 from stop 34. The control member 15, biased by the driving force of the wound-up spiral spring 16, is thus released and turns impactwise in counterclockwise direction until the stop 35 (FIG. 2) abuts agm'nst the latch nose 32 of latch lever arm 27. This rotary jump of member 15 causes an abrupt rotary switching of the cam surfaces of control cams 8, 9 and 10, relative to their cam followers, from the first to the second cam control position, the latter of which controls the stitching of the first cross tack of the buttonhole. This abrupt switching of the cams prevents the formation of undesirable intermediate stitches that belong neither to the first side bar nor to the first cross tack of the buttonhole being sewn.

Since, in comparison to the side bars of the buttonhole, only a few cross-tack stitches must be made, the pair of dogs 44 and 45 for producing the required control movements, as well as the pair of dogs 46 and 47 which follow at some distance therefrom, are located closely behind each other and the relative location of each pair of dogs along the periphery of the sleeve 24 is adjustable by means of respective screws 48, 49 for permitting a correction of the individual buttonhole side-bar lengths.

The next following control operations for producing the second side bar and. the second cross tack as well as the final sewing-over of the buttonhole take place in a manner analogous to that described above. The drive shaft 1 performs a single full revolution during production of a single buttonhole. For that reason, all stops 34 to 38 of each control member 15 come into engagement once with the latch noses 32 and 50 of the latch-lever arms 27, 31. After completion of a full revolution of the drive shaft 1, thecontrol member 15 with control cams 8, 9 and has also performed a full revolution so that the pre-tensioning of the spiral spring 16, adjusted with suchpre-tension prior to the first control operation, is preserved.

The handle portion 51- of the latch' lever 27, 31 as well as the knurled portion 52 of the sleeve 24 can be actuated in order to adjust the beginning location of a stitching pattern (in the present example the start of the first side bar of abuttonhole) and also to adjust the pre-tension of the spiral spring 16. 7

According to another feature or sub-combination of the invention, the arm structure 52a (FIG. 7) of the sewing machine is provided with a slider 59 which permits manual adjustment of the stitching-area position and adjustment of the automatic control of that position. The slider 59 (FIGS. 7, 8) is displaceably mounted on an arm 56 whose hub 57 is concentrically seated on a sleeve 58 fastened on a base plate 16a (FIG. 8). The arm 56 controls the slider block of the control mechanism in known manner. 7

FIG. 8 corresponds, generally, to FIG. 21 of copending application Serial No. 665,555 of Klaar et al. assigned to the assignees of the present invention, and the detailed description of the components therein illustrated is more fully described in that copending application. However, for purposes of better understanding the present invention, a description of the slider 59 and control member 56 is also included below.

The slider 59 is displaceably mounted on the arm 56 and carries a nose 60 (FIG. 8) which cooperates with a recess 61 in an arresting or stop plate 62. The arresting 7 plate 62 is fastened by screws on a stop member 63 the slider is placed into automatic position A (FIG. 7),

the pin 65 becomes coupled with the lever 67 and the nose 60 is placed out of its active position, thus effecting auto- The arm 75 carries a pivot pin 76which is rotatably mounted on the plate 16a and is firmly connected by a:

screw 78 with an arm 77 (FIG. 7). A boss 79 in arm 77 guides itself beneath a slide bridge 81. Arm 77 carries a handle 80 which permits turning the arm 77 along a scale 82. A change in position of armf 77 about. the axis of pivot pin 76 causes a corresponding angular displacement of the arm 75. and of the pivot pin 74 of swing lever 71, thus varying theactive leverage of swing level. 71. In this manner, the rotating speed of the stepping: mechanism 91 can be manually controlled. The stepping mechanism 91 (FIG. 7) drives the above-l described earn driveshaft 3 (FIGS. 1', 3, 7, 9). The cams 8, 9, 10 (FIG. 3) cooperate, as already mentioned, with the follower levers 11, 1'2, 13 respectively. As shown in FIG. 7, the cam 8 for the automatic control of the stitching-area position'is in driving connection with the.

matic control of the stitching area by means of link 116, a

The'device, shown in FIGS. 7 to 9 has ashaft 353 (FIGS. 9, l5) driven from the main shaft in the arm structure of'the sewing machine. 'Ihe shaft 353 carries a double eccentric 69 I (FIG. 9) acting upon an arm 70 of a bifurcated swing lever 71 which is biased counterclock wise by a spring 72'(FIGS.'7, 9) and serves as the driver of a stepping mechanism formed by a roller clutch 91. The bifurcated portion of swing lever 71 engages a driving roller 88 pivoted on the driven oscillating drive structure of the roller clutch. 7

The swing lever 71 is pivoted by means of a bushing 73 on a pivot pin 74riveted to an arm 75 (FIG. 7).

nose 114 (FIG. 7) of the feeler lever 11. Connected with the feeler lever 11 by means of a screw bolt 117 is a lever arm 116 Whose other end is linked to the above-. mentioned lever 67 by means of the bolt 11%. A spring 119 acts upon the lever 116 and biases the feeler lever 11 clockwise so that its nose 114 is held against the contour of cam disc 8.

For removing from the drive shaft 9, 10 and the stepping mechanism is connection there with, there is provided a lever 187 which is pivoted on a stationary pin 191 and acts upon the extensions 184 of the feeler levers 11, 12, 13 inorder to lift them off the cam discs 8, 9, 10. 1-

In the embodiment of FIGS. 10-13, the shaft 101, corresponding to shaft 3 of FIGS. 1-9, has a key engaging a groove 103 of a bushing 300 placed upon the drive shaft 101. The bushing 300 has a flange portion 301 (FIG. 10) and is rigidly joined together with a toothed or serrated disk 305 by a cross pin 304 (FIGS. 10, 11, 12.,

l3 The disk 305 carries on the lower side of its cylindershaped portion 306 a circle of'saw-like teeth 307 engaged by an entrainer 308 (FIG. 11) of a coupling lever 309. The lever 309, made of spring steel for resiliency, has ring-shaped configuration and comprises -a sector 312 fastened on flange 310 by means of rivets 311 (FIG. 12)- which merges with an outwardly extending sector 313 having a stop finger 314 and the above-mentioned en- 7 trainer-308. Fastened to the flange 310 by means of screws 315 (FIG. 10) are the cam disks 192, 193 and l94'whichycoa-ct with the cam followers 107, 115, 124 (FIG. '13) and serve for controlling the stitching width, the stitching-area position and the materialfeed respectively. The cam disks 192, 193, 194 and the flange 310 are free-wheelingly seated on the bushing 300 and form together with the coupling lever 309, the toothed disk 305, and the bushing 300 an independent structural unit which can readily be installed onto the drive shaft 101 and can easily be exchanged for another set of cams.

The individual cam disks 192, 193,194 can be given such a cam surface contour that they automatically control the individual side-bar and cross-tack stitches of a button- 'hole or other sewing pattern as well as the sewing-over operation during a single full rotation of the'cam shaft.

The finger 314 of coupling lever 309 (FIGS. l1, l3)

acts'upon a stop 317 which is fastened by means of a extensions 183, 184, 185 acted upon by a release lever 187, The release lever 187 is rotatable about a fixed pivot pm 191 and serves for lifting the follower levers 107, 115, 124 off the respective cam disks 192, 193, 194 when the set of dam disks is being other set. v

3 the cam discs 8,

exchanged for' an- As mentioned, the cam disk 193 (FIG. 12) cooperates with the nose 114 of the follower lever 115 for control of the stitching-area position. Connected with the follower 115 by a screw 117 is a link 116 whose other end is pivotally connected by a bolt 118 with the lever 67. A spring 119 acting upon the link 116 urges the follower 115 clockwise until the nose 114 abuts against the cam contour of cam disk 193.

The operation of the device described above with reference to FIGS. 7 to 13 is as follows.

When producing closed groups of stitch patterns, for example buttonholes in a shirt, by virtue of the automatic control performance of the set of cam disks 192, 193, 194, the rotating speed of the cam shaft 3 must be constant even though this shaft is driven from the arm shaft of the machine through a stepping mechanism 91. A change in the setting of the handle 80 (FIG. 7) would change the driving speed of the cam disks 192, 193, 194 and hence the longitudinal dimension of the buttonhole being produced. At the beginning of the sewing operation, the cam shaft 3, acting through the bushing 300 (FIG. 10) rotates the toothed disk 305 in a counterclockwise direction, as viewed in FIG. 13. Due to the elasticity of the freely movable coupling lever 309, it is biased upwardly so'that the entrainer 308 of lever 309 engages one gap of the saw teeth 307 and thereby entrains the coupling lever 309 a well as the cam disks 192, 193, 194 in the same sense of rotation as disk 305.

Shortly before, or at the moment of, the termination of the sewing operation cycle during which the first side bar, the first cross tack, the second side bar and the second cross tack of the buttonhole have been sewed and the completed buttonhole may have been sewed over as the last step of the cycle, the finger 314 of coupling lever 309 passes beneath the portion 319 of the upwardly extending stop 317 on follower lever 115. Finger 314 is thus forced downwardly, relative to FIG. 12, i.e. at right angles to the circular motion path of finger 314, so that the entrainer 30$ disengages itself from the teeth 307, thereby immediately stopping the flange 310 and the cam disks 192, 193, 194 connected thereto, but without thereby interrupting the rotation of the drive shaft 101.

The contour design of the cam disk may be so chosen that the cam driving motion is terminated immediately before termination of the last sewing operation, that is prior to terminating the sewing-over step, with the result that the seamstress has suflicient time to bring the sewing machine to a standstill. However, if a sewingover operation on the buttonhole is not desired, then the drive of the cam disk may be interrupted, for example, when passing from cross-tack sewing to the sewing of the next following side bar.

After completing the buttonhole in standstill condition of the cam disks, and after selecting the next location on the fabric to be provided with another buttonhole, the slider 59, placed in automatic position A, is manually moved together with its arm 56 toward the right relative to the illustration in FIG. 7. This causes the link 116 to turn the cam follower 115 with the stop 317 counterclockwise about the pivot point 122 (FIGS. 7, 13) in opposition to the action of the tension spring 119. As a result, the finger 314- of the coupling lever 309 is released from under the part 319 and, due to its elastic pre-tensioning, is flung upwardly thus resuming its coupling position. In this position, the entrainer 308 again engages the saw teeth 307. The engagement may occur in any position of the toothed disk 305. When the slider 59 returns to its original position, relative to FIG. 7, the part 319 of stop 317 is shoved beneath the finger 314 of coupling lever 309 Without disturbing the motion of the coupling lever at the beginning of the following machine operation.

It is, of course, possible and within the scope of the invention, to mount the control cam 192 for the stitching width or the control cam 194 for the material feed in such a manner, and in lieu of the cam disk 193 for the automatic control of the stitching-area position, that the appertaining follower lever 107 or 12-4 is provided with the stop for the coupling lever 309. Thus, with an analogous design of the correlated, not illustrated, manual control switching means, the coupling lever 309 and the cam disks 192, 193, 194 can be controlled in the same manner as described above with reference to the control effected by the cam disk 193.

Although the impact actuating means 16 has herein been illustrated as a spiral spring for storing mechanical energy, it is also within the scope of this invention, and will be apparent to those skilled in the art upon reading of this disclosure, that other impact actuating means, such as, for example, electrically controlled actuating means operated by solenoid or the like, can be used as means for actuating the release lever 39 or for rotating the control member 15 at the proper time in the cycle of cams 8, 9, 10.

It will be understood by those skilled in the art, upon a study of this disclosure, that the invention is not limited to the embodiments particularly illustrated and described herein but may be modified in various respects without departing from the essential features of the invention and within the scope of the claims annexed hereto.

We claim:

1. In a zigzag sewing machine equipped with a laterally movable needle bar and a material feeding device, cam means and cam follower means for regulating the motion of said needle bar and feeding device to thereby control the stitching length, stitching width, stitching area position and material feed direction, said cam means having a plurality of control surfaces for automatically producing respective portions of an enclosedarea stitch pattern; an intermediate stepping mechanism having manual speed-regulating means and connected for normally driving said cam means to given cam positions at an adjustable rate of speed, and a control device for accurately producing said enclosed-area stitch pattern comprising impact actuating means operably connected to said cam means for effecting an abrupt switching of said control surfaces of said cam means relative to said cam follower means to abruptly relocate the latter, after said stepping mechanism has effected a given cam position, from a first one of said surfaces which produces a first portion of said pattern to a subsequent one of said surfaces which produces a subsequent portion of said pattern, whereby the formation of undesirable intermediate stitches betwcen said first and subsequent pattern portions and between the termination of one pattern and the beginning of a subsequent pattern is prevented.

2. In a zigzag sewing machine equipped with a laterally movable needle bar and a material feeding device, cam means, drive means for rotating said cam means, and cam follower means cooperating with said cam means for regulating the motion of said needle bar and feeding device to thereby control the stitching length, stitching width, and stitching area position, said cam means havmg a plurality of control surfaces for automatically producmg respective portions of an enclosed-area stitch pattern; a control device for accurately producing said enclosed-area stitch pattern comprising force storing means operably connected to said drive means for receiving energy into said force storing means from said drive means, a control member operably connected between said force storing means and said cam means, and releasing means for releasing said force storing means to rapidly move said control member so as to effect an abrupt switching of said control surfaces of said cam means relative to said cam follower means to abruptly relocate the latter from a first one of said surfaces which produces a first portion of said pattern to a subsequent one of said surfaces which produces a subsequent portion of said pattern, whereby the formation of undesirable intermediate a l l stitches between said first and subsequent pattern portions and between the termination of one pattern and the beginning of a subsequent pattern is prevented. l v Q Q 3. a In a zigzag sewing machine equipped with a laterally movable needle bar and a material feeding device, cam means, drive means for rotating said cam means, and cam follower means cooperating with said cam means for regulating the motion of said needle bar and feeding device to thereby control the stitching. length, stitching width, and stitching area position, said cam means having a plurality of control surfaces for automatically producing respective portions of an enclosed-area stitch pattern; a control device for accurately producing said enclosedarea stitch pattern comprising a spiral spring for storing mechanical energy, a control member joined to one end of said spiral spring for being driven thereby, the other end of said spiral spring being operably connected to said drive means for receiving energy therefrom for storage in said spiral spring, said control member being operably connected to said cam means, latch means for engaging said control member to arrest the latter and'thus to retain said oneiend of said spiral spring in stationary posi tion, releasing means for disengaging said latch means, whereupon the stored energy in said spiral spring drives said control memberto rapidly move the latter so as to effect an abrupt switching of said control surfaces of said cam means relative to said cam follower means to abruptly relocate the latter from a first one of said surfaces which produces a first portion of said pattern to a subsequent one of said surfaces which produces a subsequent portion of said pattern. i

4. In a zigzag sewing machine equipped with a laterally having manual speed-regulating means and connected movable needle bar and a material feeding device, cam

7 area stitch pattern comprising a spiral spring for storing mechanical energy, a control member joined to one end of said'spiral spring for being driven'thereby, a control shaft connected to the otherend of said-spiral spring and operably connected to said drive means for transmitting energy therefrom for storage in said spiral spring, said control member being operably connected to said cam means, latch means for engaging said control member to arrest the latter and thus to retain said one end of said spiral spring in stationary position, releasing means for disengaging said latch means, whereupon the stored energy in said spiral spring drives said controlmember to rapidly move the latter so as to effect an abrupt switching of said control surfaces 'of said cam means relative to said cam follower means to abruptly relocate the latter from a first one, of said surfaces which produces a first portion of said pattern to a subsequent one of said surfaces which produces a subsequent portion of said pattern.

5. In a zigzag sewing machine equipped with a laterally movable needle bar and a material feeding device, cam means, drive means for rotating said cam means, and cam follower means cooperating with said cam means for regulating the motion of said needle bar and feeding device to thereby control the stitching length, stitching width, and stitching area position, said cam means having a plurality of control surfaces for automatically producing respective portions of an enclosed-area stitch pattern; a control device for accurately producing said enclosed-area stitch pattern comprising a spiral spring for storing mechanical energy, a control member joined to one end of said spiral spring for being driven thereby, a control shaft connected to the other end of said spiral spring and therethrough to said cam means, an intermediate stepping mechanism cam follower means to abruptly relocate the latter from a first one of said surfaces which produces a first portion of said pattern to a subsequent one of said surfaces which produces a subsequent portion of said pattern.

6. A control device according to claim 5,;said latch means comprising stop means mounted on said control member and a latch lever having nose means for engaging said stop means.

7. In a zigzag sewing machine equipped with a lat-1 erally movable needle bar and a material feeding device, cam 'means, drive means for rotating said cam means, andcam follower means cooperating with said cam means for regulating the motion of said needle bar and feeding device to thereby control the stitching length, stitching width, and stitching area position, said cam means having a plurality of control sectors for automatically producing respective portions of an enclosed-area stitch pat-' tern; a control device for accurately producing said enclosed-area stitch pattern comprising a spiral spring for storing mechanical energy, a control member joined to one end of said spiral spring for being driven thereby, a control shaft connected to the other end of said spiral spring and operably connected to said drive means for transmitting energy therefrom for storage in said spiral spring, said control member being operably connected to said cam means, latch means comprising stop means mounted on the periphery of said control memberand further comprising a latching lever having nose means for engaging said stop means to arrestsaid control meniber and thus to retain said :one end of said spiral spring in stationary position for storage of energy in said spiral spring during rotation of said control shaft, releasing means for disengaging said latch means from said stop means, said releasing means comprising a releasing lever adjustably connected with said latching lever and including sleeve means rotatably mounted relative to said control member and fixed to said control shaft for rotation therewith and with said other end of said'spiral spring, said sleeve means having dog means mounted on the periphery thereof for engaging said releasing lever :to thereby disengage said latching lever from said stop means, whereupon the stored energy in said spiral spring drives said control member to rapidly move the latter so as to effect anabrupt switching of said .control sectors of said cam means relative. to said cam follower means to abruptly relocate the latter from a first one of said sectors which produces a first portion of saidpat-tern to a subsequent one of said sectors which produces a subsequent portion of said pattern.

8. A control device according to claim 7, said dog means being displaceably mounted on the outer periphery of said sleeve means for circular adjustment thereof on said periphery, to thereby adjust the instant in the rotary cycle of said cam means at Which'said abrupt switching of said control sectors takes place.

9. A control device according to claim 7, said latching lever and said sleeve means having respective manual,

setting members for adjusting the pre-tension of said spiral spring and for manual adjustment of cam means.

=10. 'In a zigzag sewing machine according to claim 7 13 said control shaft being removably mountable on said 2,194,243 drive means. 2,871,702 2,983,240 References Cited in the file of this patent 3 001 491 UNITED STATES PATENTS 5 660,634 Guett Oct. 30, 1900 524,634 1,891,101 Lecount Dec. 13, 1932 552,428 2,073,983 Anderson Mar. 16, 1937 554,537

14 Kronmiller et a1 Mar. 19, 1940 Tetro Feb. 3, 1959 Engel May 9, 19'61 Engel Sept. 26, 1961 FOREIGN PATENTS Italy Apr. 28, 1955 Italy Dec. 3, 1956 Belguim Feb. 15, 1957 

1. IN A ZIGZAG SEWING MACHINE EQUIPPED WITH A LATERALLY MOVABLE NEEDLE BAR AND A MATERIAL FEEDING DEVICE, CAM MEANS AND CAM FOLLOWER MEANS FOR REGULATING THE MOTION OF SAID NEEDLE BAR AND FEEDING DEVICE TO THEREBY CONTROL THE STITCHING LENGTH, STITCHING WIDTH, STITCHING AREA POSITION AND MATERIAL FEED DIRECTION, SAID CAM MEANS HAVING A PLURALITY OF CONTROL SURFACES FOR AUTOMATICALLY PRODUCING RESPECTIVE PORTIONS OF AN ENCLOSEDAREA STITCH PATTERN; AN INTERMEDIATE STEPPING MECHANISM HAVING MANUAL SPEED-REGULATING MEANS AND CONNECTED FOR NORMALLY DRIVING SAID CAM MEANS TO GIVEN CAM POSITIONS AT AN ADJUSTABLE RATE OF SPEED, AND A CONTROL DEVICE FOR ACCURATELY PRODUCING SAID ENCLOSED-AREA STITCH PATTERN COMPRISING IMPACT ACTUATING MEANS OPERABLY 